Atoll Blog article (co-writen with Chatbot ChatGPT-5 / o3, uploaded 6th August 2025) explores disturbing environmental commonalities and causal effects, linked to continuing public ignorance and indifference to lifestyle food choices that contribute through their production and agriculture to excessive nitrogen and phosphorus pollution of our rivers, (and , via their eventual outflows, our seas). In both UK Rivers and North Atlantic, a key species at the forefront of this decline is the now critically endangered European eel with only 5% of its original population now remaining in the UK. These mysterious Ray-finned fish provide the common link through their long and arduous migration cycle, spanning between UK riverine habitats like the failing River Wye and distant Sargasso Sea spawning grounds, mid Atlantic.

A Cautionary Tale of Slippery Eels and Sargassum Belts with a Rum Punch

In the Wide Sargasso Sea, the 1966 historical novel by Dominican-British author Jean Rhys, set in Jamaica between the 1830-40s, one of its most powerful and frequently cited quotes is: “I hated the mountains and the hills, the rivers and the rain. I hated the sunsets of whatever colour, I hated its beauty and its magic and the secret I would never know. I hated its indifference and the cruelty which was part of its loveliness”.

‘Relational Ambivalence’ and contradiction also apply to modern attitudes and our almost unconscious unwillingness to compromise comfortable lifestyle and luxury, whilst convincing ourselves we are mindful and sympathetic to the greater good of sustainable practice. Our appetites for cheaply produced convenience food, whilst remaining in denial about the morals of where it comes from, and the global consequences from a whole raft of linked side effects, are a case in point. The ecological implications from our everyday actions (or inactions) reach far beyond our home hinterland with their polluted rivers and these plume out into the ‘great blue’ of our planet – the great circulatory oceans – to slowly but inevitably wreak havoc.

The open North Atlantic, bounded by its great shifting circulatory currents and Gulf Stream, hosts one of the most ecologically curious regions of any ocean: The Sargasso Sea, surrounded by a vast gyre around it’s centre – neither enclosed by land nor confined by coast – is famous for its golden brown floating algae. Called Sargassum, this has historically formed a stable ecosystem of shelter and sustenance for juvenile turtles, fish, and invertebrates. Yet in recent years, this once stable marine habitat has been implicated in a planetary-scale anomaly. But since around 2011, scientists have observed a dramatic increase in Sargassum biomass – not in the Sargasso Sea itself, but thousands of kilometres to the south, along a band stretching from West Africa to the Gulf of Mexico. This phenomenon, now known as the Great Atlantic Sargassum Belt, has grown to the point where it can span over 8,000 kilometres in a single bloom event, releasing millions of tonnes of seaweed onto Caribbean beaches, smothering coral reefs and seagrass beds, and producing toxic hydrogen sulphide gases as it rots on land.

The causes of this sprawling belt are layered and deeply interconnected with changing land and ocean dynamics. A key factor is nutrient loading: excess nitrogen and phosphorus flowing into the tropical Atlantic from the Amazon and Congo basins, as well as West African river systems. Agricultural expansion — particularly soy and cattle production in Brazil and oil palm in West Africa — is increasing the volume of fertiliser runoff and sediment reaching the ocean. In parallel, Saharan dust blown westward provides additional iron, which may stimulate blooms when combined with riverine nutrient flows. At the same time, global warming is heating up surface waters and altering current patterns, shifting the Intertropical Convergence Zone and promoting stagnant, stratified conditions ideal for macroalgae proliferation.

The science is still evolving. Recent studies suggest that vertical mixing in the tropical ocean may play a more important role in nutrient delivery than previously thought. But whether sourced from rivers, winds, or ocean turbulence, the cumulative effect is clear: a deepening crisis of macroalgal overproduction that threatens coastlines and economies throughout the tropical Atlantic. In response, governments and civil society are beginning to explore sustainable reuse options. In Barbados, a distillery-to-biogas initiative is processing Sargassum biomass along with wastewater from rum production to generate renewable energy to drive cars and be used as agricultural fertiliser. While far from a panacea, such approaches suggest the possibility of circular solutions within otherwise destructive feedback loops.

Just over 6,000 kilometres northeast, along the banks of the River Wye in Wales and western England, a different nutrient crisis is unfolding. The river, long cherished for its biodiversity and famed in local myth and literature, has become the site of repeated algal blooms and ecological decline. Once a haven for water crowfoot, kingfishers, otters, and the elusive European eel, the Wye is now increasingly choked by green algae — a phenomenon linked not only to direct sewage discharge, but also to large-scale poultry and dairy operations across its catchment.

Phosphate is often cited as the primary culprit. The expansion of intensive livestock units has generated thousands of tonnes of surplus manure, much of which is spread on land already saturated with phosphorus. When it rains, this phosphate-laden runoff finds its way into streams and rivers, fertilising blooms that then disrupt aquatic food chains. Yet recent independent research by Cardiff University, commissioned by the Wye & Usk Foundation’s Wye Algae Project, challenges the singular focus on phosphorus and claims it is a ‘silver bullet’. Their findings indicate that while phosphate levels in many stretches of the river have actually decreased and are now within conservation targets, blooms continue to worsen. The likely explanation lies in a more complex interaction between nitrogen spikes, ammonium loading, low summer flows, and elevated temperatures — all of which combine to create a river environment ripe for algal takeover.

At the heart of this river’s story is one of Europe’s most remarkable and mysterious species: the European eel (Anguilla anguilla). Now classed as critically endangered, in the last 25 years, the species has experienced a catastrophic decline, with a 95% reduction in its population across Britain. These catadromous fish begin life as transparent larvae in the Sargasso Sea, drifting for months across the Atlantic before entering European rivers, where they grow and mature for years — sometimes decades — before returning to their Sargasso birthplace to spawn and die. This migration, long steeped in folklore and myth, now confronts profound ecological barriers. Weirs and hydroelectric structures impede movement. Polluted freshwater reduces juvenile survival. Rising ocean temperatures may be shifting spawning cues. And the collapse of the Sargasso Sea ecosystem under the weight of open-ocean Sargassum blooms raises broader questions about larval dispersal, prey availability, and the long-term habitability of this already fragile nursery ground.

These pressures have not gone unnoticed. The Convention on Migratory Species (CMS) recognises the European eel as a species of concern, and organisations such as the Sustainable Eel Group in the UK and global initiatives like World Eel Day campaign for habitat restoration, stricter fishery controls, and improved migration pathways. Yet progress remains slow. Legal protections are patchy, and regulatory enforcement across river catchments is often fragmented. A recent investigative documentary, Rivercide, fronted by writer and campaigner George Monbiot, exposed the scale and systemic nature of pollution in rivers like the Wye. His call for an emergency clean-up plan and moratorium on new intensive livestock units resonated with many, though government action has so far been limited. Nonetheless, the film sparked a wave of citizen activism, bolstering the efforts of local and national campaign groups such as Save the Wye, Friends of the Upper Wye, and the CPRE.

Meanwhile, international efforts to safeguard the oceanic end of the eel’s life cycle are gaining traction. The Sargasso Sea Commission, supported by the Government of Bermuda and a growing alliance of scientific institutions, seeks formal recognition and protection of the Sargasso Sea under high-seas governance frameworks. Their campaign feeds into broader pushes for oceanic protection, including the Global Ocean Treaty and the “Hope Spots” programme from Mission Blue. Environmental organisations such as Greenpeace UK and partners under the High Seas Alliance are lobbying for stronger enforcement and equitable benefit sharing under these treaties, especially as deep-sea mining and climate disruptions threaten migratory corridors and spawning grounds.

The connections between the Sargasso Sea and UK rivers are more than symbolic. They are biophysical, ecological, and existential. Excessive nutrients — whether from Amazonian deforestation or British poultry farms — are disrupting natural cycles at both ends of the eel’s migration. Warmer waters and shifting currents — whether off the coast of Ghana or Gloucestershire — are altering the rhythm and reach of species that depend on predictable flows. And in both cases, human inaction, fragmented governance, and commercial inertia continue to widen the gap between knowledge and response.

Yet hope lies in convergence. The push for nutrient management in river catchments, when properly enforced and coordinated, reduces pressure downstream. Protection of oceanic gyres like the Sargasso Sea, when embedded in international law, secures migratory lifelines upstream. Circular economy innovations, such as converting Sargassum into biogas or compost, offer models for resilience rather than reaction. And through the collective voice of campaigners, scientists, NGOs, and affected communities, the groundwork is being laid for an integrated ecological recovery.

This is not just about eels, seaweed, or rivers. It is about the circulatory systems of the planet — the slow-moving exchanges of matter and meaning between land and ocean, algae and animal, myth and metabolism. The Wye and the Sargasso are joined by more than a migratory species. They are united by a warning — and perhaps, if we are willing, a chance.

POSTSCRIPT (Rights of Rivers)

There are growing environmental and community movements in the UK calling for the recognition of our rivers as sentient beings – and so, looking to grant them (and other key natural environments) ‘legal personhood’. This is not a new cultural phenomenon though, as many indigenous cultures around the world have subconsciously known this for millennia. Our own ‘Rights of Rivers’ movement has a long way to go still in the UK, but at least public and political awareness around flood mitigation, sewerage outfalls, agricultural and chemical pollution, and sustainable urban drainage is growing nationally. 

Earth Law Center runs an initiative to define the basic rights to which every river is entitled: the Universal Declaration of River Rights. You can read about it here and read and sign the declaration here.